(a) Field of the Invention
The present invention relates to a transfer apparatus, and particularly to a transfer apparatus for transferring a large size glass substrate.
(b) Description of Related Art
In general, a transfer system or apparatus utilizes a conveyor apparatus to move a transfer object by placing the transfer object onto a conveyor which works in conjunction with an operating roller connected to an operating motor.
The conventional conveyor system uses the operating motor to provide power to move the transfer object and a chain, a gear, or a belt for the purpose of power transfer. Disadvantageously, the belt or chain may break or wear out causing maintenance problems and manufacturing delay.
Furthermore, since dust is generated due to the driving of a motor, the motor is arranged apart from the remainder of the conveyor system so as not to affect the transfer objects, such as semiconductor devices or liquid crystal displays (“LCDs”), in which cleanliness is an important issue. Therefore, because the motor is isolated from the place where the object is transferred, the operation is made more difficult, the system is more complicated, and the cost is increased.
Dust problems also arise with the use of gears. For a conventional apparatus, since one motor should drive a plurality of driving axes, a medium for transferring power, such as a gear, is required between each driving axes, which causes the dust problems indicated above.
If a motor and a conveyor belt are used, a noise problem also arises. The noise from machinery disturbs the operator or administrator, which decreases operation efficiency.
A transfer system or apparatus can be utilized to transfer glass substrates used in manufacturing liquid crystal displays (“LCDs”). An LCD is one of the most popular flat panel displays, which includes two panels provided with two kinds of electrodes generating an electric field and a liquid crystal layer interposed therebetween. The LCD displays images by controlling light transmittance, and the control of the light transmittance is performed by applying voltages to the electrodes to generate electric fields which change the arrangement of liquid crystal molecules.
The panels of an LCD can be transferred to processing devices used in the manufacturing process by using the transfer system. Conventionally, a plurality of glass substrates are transferred to a processing device using a cassette, a stocker, and an indexer. However, as glass substrates are getting larger, the conventional transfer system using the cassette, stocker, and indexer becomes harder to use and manage due to inflexibility and unwieldiness.
Various conventional transfer apparatuses such as conveyors, robots, stockers, AGVs (automatic guided vehicles), etc. have been enlarged in order to accommodate enlarged glass substrates. However, disadvantages remain with conventional systems and apparatus, such as generation of static electricity, decreased yield accompanied by contamination, and generation of cracks due to the contact between the glass substrate and the conveyor belt. Thus, there is a need in the art for a transfer apparatus that is flexible and clean and that transports objects securely without damage.